Beijing prepares to convert taxis to electric or hybrid power, Sadiq Khan plans to ban diesels from central London by October 2018 and mayors in Madrid, Paris, Athens and Mexico City have similar plans it looks like we’re going to say goodbye to the dirty- but fun- diesel engine. Car trade in schemes are emerging around the world.
Diesels for years were touted as slightly more environmentally friendly, in certain circumstances, than petrol engines. Over long distances they are, further n average they produced 15% less carbon dioxide than petrol, meaning excise duties were less. Hindsight is 20/20 though.
The current language we have for talking about emissions, greenhouse gases and climate change is too broad. A lack of education and marketing mis-direction neatly concealed diesels habit of emitting far more nitrogen dioxide, which has much greater Global Warming Potential and also great deal of particulate matter as a result of combustion. The tiny radicals able to reach your lungs, heart and brain and cause serious illness.
Car Trade-In Schemes
In 2009 the UK government offered owners of cars 10 years or older £2,000 off a new vehicle. The scheme opened questions about gaming the system, hence the 10 year minimum on ownership as a prerequisite. Nearly 400,000 cars were sold through the scrappage scheme. The purpose of the scheme was not entirely ecological. 2008 had just happened. The economy was in dire straits and in need of input from consumers to get things flowing again.
Car manufacturers themselves have offered similar schemes, Vauxhall (known as Opel elsewhere in the world) offered up to £2,000 off their range of cars. The cars bought through the scheme emitted on average 27% less than the scrapped vehicles. Now work is taking place in the UK to launch another car trade in scheme, specifically aimed at parts of the country where pollution is dangerously high.
The Hidden GWP in Diesels
The following table breaks down greenhouse gases into component gases. While the amounts of GHGs lower down the table are usually emitted in much smaller amounts. GWP is a relative measure, anchored to carbon dioxide, of how much heat is trapped in by presence of the gas.
Diesel is heated and pressurised to the point of combustion. Gasoline engines receive power by controlling the air-fluid mixture which is ignited by a spar. This difference means diesels run hotter and need higher pressure for combustion and thus movement. The consequence of this is nitrogen oxide production 20 times greater than petrol engines.
The ideal alternative for the trade in would be an electric car. Except we currently lack the infrastructure and indeed technological distribution, to make them a reality. Not to mention clean electricity generation in the first place. The range on electric vehicles currently maxes out at 200 miles. The charge time is also very slow in comparison. Shifting away from diesel and fossil fuelled cars in general is going to require a lot of work, but its essential.
If government and industry work together car trade in schemes can be timed to ensure a smooth transition to a cleaner transportation system.